This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. SHP-2 is a protein tyrosine phosphatase that is activated by sporadic point mutations in myeloid leukemias, and similar mutations in the germ line cause Noonan Syndrome. A variety of studies have implicated SHP-2 in regulation of Ras and/or MAPK signal transduction. In leukemogenesis, this requires the function of several protein interaction domains of SHP-2, including two SH2 domains, the catalytic phosphatase domain, and a carboxyl terminus that includes two potentially phosphorylated tyrosines. The goal of this project is to describe the protein interaction partners of leukemogenic SHP-2 in a model myeloid cell line using affinity purification. The UCSF Mass Spectrometry Facility will determine the peptide content of purified lysates, providing a list of candidate molecules for mediating the biologic action of SHP-2.